First of all, I want to thank Wid for helping me resolve 1 of the three problems I have, thanks Rick!

As most of you know I received my Emotiva mps-1 amp chassis recently plus two of their epm-300 monoblock modules for starters to drive my m80's. The amp is very cool and top quality.

Anyway, I have some issues as I'm hearing some static in the m80 tweeters occasionally. In addition, I've been hearing a slight "hum" from the woofers, and what sounds like pink noise emitting from the tweeters at a very very low level (have to put my ear right up against the tweeters) when I don't hear the static mentioned above.

Anyway, below is a post on my thread I started on AV123, as their are many Emotiva owners on that website. Was hoping for some ideas from my Axiom buddies.

.........................

With the help of one of my Axiom buddies, "Wid", I made some progress. It appears the static sound and hum situation are two different animals. I'll talk about the static in a bit.

First of all, I took the screws out of the epm300's that secure it to the chassis and that seemed to make no difference for any of my issues, so I put them back in...

In troubleshooting the "hum" I noticed I was getting some hum out of my center speaker which was not hooked to my mps-1. I thought this was odd. My monster Axiom ep600 sub is placed right below my center speaker about 1 ft. The center speaker is mounted on the wall below my screen. I noticed when I unplugged the sub, the hum went away. Also, the hum that I was hearing in my m80 mains reduced somewhat.

The Axiom subs have a ground screw you can remove if you hear the 60hz hum in the sub. So I removed the screw and plugged the sub back in, and shazaam, the hum from the center disappeared and the hum from the mains was greatly reduced. So my guess is something was feeding back through the "Blue Jeans" coax to my receiver and creating a hum in the speakers.

I still have the hum in the mps-1 amps I can hear from 5-6" away, and there is still a very small hum in my main speakers which appear to be originating from the amp. Not sure if this is normal? I'm thinking if I was using speakers that were not as efficient, I would not hear anything from them?

Another thing I didn't mention before, and not sure if this is a problem, is that I didn't place the two epm-300 mono's right next to each other. I placed one in the first slot and placed the second one in the third slot over. I figured this would give a little more air flow. I plan to purchase one more to drive my center, and then 2 of the 2-channel epm-2150's for the surrounds. So I'll have plenty of room.

In regards to the static sound I hear. This is a weird problem. AT first I thought it was cable related, but after using the better cables I purchased tonight at Radio Shack, the static noise was still in the tweeters of my mains. It was not consistant, sometimes it was there, and other times it was not. I was freaking out.

Then I noticed that it had to do with the light switch in my AV closet. When I had the close light ON, there was no static. When I turned the light OFF, the static could be heard in the tweeters. That to me is very strange, you would think it would be the opposite.

It gets better, the light switch for my closet light is on a totally different circuit. I have a dedicated 20amp circuit for my AV stuff. The closet light switch is on a different 15amp breaker for other lights in the basement.

So then I went and turned off the 15amp breaker for the closet light, and the static was still present. It is only when the light is turned on, that the static goes away, and the only thing is the hum from the amp.

The bulbs are just your normal white colored 60-75 watt bulbs you buy at walmart, I think they are GE, nothing expensive.

I'm puzzled because this static sound shows up in the tweeters when the switch is OFF, not ON. Also, being on a different circuit puzzles me. Now in the breaker box, these two breakers are next to each other, not sure if that would play a role. When I turned off the 15 amp breaker for the lights in the rec room, which includes the close light, I still hear the static. It is only when the circuit is active and the lights are ON.

You said you have the HT on an independent circuit. Do you know if it shares a neutral with that lighting circuit, or was the wiring home ran to the panel for the HT circuit? If they are sharing a neutral, the circuit path will still be routed through the lighting fixture (neutral to ground) regardless of whether the light switch is open or closed. If any of the fixtures on that circuit are not properly grounded to the ground wire, you could be getting feedback on the neutral. I’m not saying this is your culprit, but it ‘could’ be.

Let me know and I’ll run this scenario by one of the EE’s at work to see if they have any ideas.

I just talked to a guy at work who is pretty good with electrical stuff. He said to first check to obvious stuff like the ground wire, etc.

I think I'm getting some type of interference on the secondary ground (bare wire). He said often it will act like an antenna. I also don't think it is coming from the 15amp circuit the light switch is on, because I turned that breaker off and still hear the static. He said it is possible that when I turn the light ON, it is "absorbing", if you will, the static, that is why I don't hear it when the light is on.

It sounds like since I have the Primary Ground (larger lug) I can remove the "secondary ground" from the Green screw on the outlet and see if that eliminates the static from the amp/speakers. Unless of course the static is coming from the primary ground.

I agree with Mike in that with the breaker for the light switched off, the Neutral (White) wire is still connected and may be shared with your dedicated theater circuit.

I think you are on track in checking the ground (bare wire) to the light fixture and the light switch, and even the theater outlets. They should all be connected, and the source of the problem is probably a missing ground, and/or a device introducing noise into the ground or Neutral. You could go around unplugging everything on the other circuit to see if the hum quits.

If that doesn't work, you could try removing the circuits from your breaker box one at a time to find out which one may be introducing the hum into the system. To do this you may need to do more than just turning off the breakers one at a time. You probably need to locate the White Neutral wire as well and disconnect it from the panel. When you find the one that removes the hum (maybe the one with the light or not, but start there first), you know it is something on that circuit.

*** DISCLAIMER *** I am not an electrician, but I have dealt with these kinds of issues before. Hopefully others may chime in on if this would make any sense or be worthwhile. It was just an idea I had. Please be careful in what you do in the box (just want to be sure you are safe). Get someone who knows what they are doing if you need help, and turn off the power to the box before working in it.

The HT circuit is not sharing the neutral ground with any other circuit. All the outlets and switches on every circuit has the secondary ground (bare wire) twisted togethor and attached to the green screws. It is my understanding that this secondary ground can act like an antenna in certain instances, and really serves no purpose as most newer outlets/plugs incorporate the primary ground (white wire) with the larger spade on the plug, which can only be inserted one way.

Back in the day, when both spades were the same, this ground was required in the event someone reversed the hot(black) and primary ground (white). This would allow another path for the ground to take.

Anyway, the suggestion I had was to remove the secondary ground (bare wire) from the green screw on the outlet my AV equipment is plugged into. The alternative is to try to figure out which circuit is causing the problem or what appliace if any, is causing the problem. Sometimes if your ground rod is not deep enough (at least 6ft) you can have similar problems.

I'll see what I can find out, thanks for the help...

ps: Tom, the GE bulbs at Wally World are the same as at Menards, HD, etc... just cheaper.

Quote:The HT circuit is not sharing the neutral ground with any other circuit. All the outlets and switches on every circuit has the secondary ground (bare wire) twisted togethor and attached to the green screws.

Am I reading that right? That the neutral (drop the term ground for clarity - it's a neutral wire) and the ground are connected at each wall box? If that's true, then you've got a serious issue. Your neutral should only be bonded (to ground) in ONE place in the house - at the main breaker panel. Even any other pony panels should have the neutral bonding strap removed. It's code.

And if I did read that wrong, and the neutrals aren't bonded at each box, then yes, all your neutrals are eventually connected together when they get back to the breaker panel. They're all screwed into the same neutral bar.

Have you checked for a floating neutral? Look for voltage between neutral and ground at the plug.

Well actually, the neutral is bonded to ground at the meter base, not the panel.

Randy, the neutral is a current carrying conductor, not a ground. The ground wire is the one and only ground although is is sometimes mistakenly called a ground.

The reason I asked if the light circuit and HT circuit shared the neutral is because that's a common practice. Even if you have a separate breaker for both, that don't mean anything unless they are both GFCI breakers and wired to code as the neutral wire goes directly to the breaker and not the panel bonding strip.

Many electricians and builders run 12/3 romex for reasons of saving labor and material. It has three conductors and one ground (Black, Red, White, ground). This saves time because you only have to pull one run of romex back to the panel. At the most logical J-box, the electrician ties in a separate 2/12 romex for another run of devices. At this J-box, the neutrals are tied together and ran back to the panel as "shared".

Ok, please keep in mind that I'm not an electrician, and my terminology is just information I'm confusing between you guys and my friend at work that I totally trust.

Anyway, I wired my basement myself. I have 12-2 for everything. My HT equipment is on a seperate 20amp breaker with 12-2 wire run from the breaker box on one end of my basement to the HT area. Everything else in the basement, lights-outlets, etc....are on their own 15amp circuit.

From what I'm told, and I'm sure everyone has different terminolgy, the black wire is the "hot", the white wire is sometimes called the primary groud, and the bare wire is the secondary ground. The primary ground has the prong, lug, fin, pin, or whatever the terminology is, which is wider, so the plug only fits in one way. Back in the day both of they were the same size, and many plugs did not have the "third" secondary (bare) wire.

I was told I could unhook the secondary, bare wire, from the outlet my AV equipment is hooked to, and see if the "static", not hum goes away. This would tell me if I'm getting interference somewhere else in the line, which is being picked up by the secondary ground (bare wire).

Anyway, my friend from work I talked to is 60, and has been around networking and phone topologys his whole life. He gave me information to help me wire my basement, as it was not rocket science. I'm sure I'm not phraseing everything as it might be stated in the textbooks, so sorry.

Quote:I was told I could unhook the secondary, bare wire, from the outlet my AV equipment is hooked to, and see if the "static", not hum goes away. This would tell me if I'm getting interference somewhere else in the line, which is being picked up by the secondary ground (bare wire).

As MDrew said, the ground is a safety ground. It creates a pure path back to earth for safety reasons. You ground the boxes so if a loose hot wire hits the box, instead of it becoming energized, it trips the breaker. It's a safety issue.

Quote:Anyway, my friend from work I talked to is 60, and has been around networking and phone topologys his whole life. He gave me information to help me wire my basement, as it was not rocket science. I'm sure I'm not phraseing everything as it might be stated in the textbooks, so sorry.

I don't think we're picking on you for nonclemature, but for mistaken reasoning. The neutral and ground wires are there for different tasks. If you keep considering your next move with a flaw in the logic, you may end up hurt.

Quote:Well actually, the neutral is bonded to ground at the meter base, not the panel.

This (second picture under Identifying The Parts) is what I usually see. I know there seem to be a lot of differences in different places as to grounding. Some places you can still use a ground rod, I understand.

Quote:Many electricians and builders run 12/3 romex for reasons of saving labor and material. It has three conductors and one ground (Black, Red, White, ground). This saves time because you only have to pull one run of romex back to the panel.

At the most logical J-box, the electrician ties in a separate 2/12 romex for another run of devices. At this J-box, the neutrals are tied together and ran back to the panel as "shared".

Which raises another concern that never really ever gets many eyebrows raised. Not only can you overload a hot leg of a mains circuit, it is possible to overload a neutral leg. My garage for instance, picked up the two 15A circuits onto 14-3 as they came out of the concrete pad. Now each hot conductor is carrying up to a 15A load, and the shared neutral can see 30... on a 14ga. wire. Bad.

But the NEC and CEC always seem to contradict themselves. The 12-3 solution would work better, since the extra wire size would make carrying the load easier. Then I get my wrist slapped by my electrician neighbour who mentions the CEC requires any run to the panel made with 12ga has to be connected through a 20A breaker.

Randy,I didn’t mean to pick on you. Yes, in years past the neutral conductor was referred to as a ground, and also the “common” conductor. As Bren stated, it is there for safety reasons. When I was an apprentice back in the early 90’s, my mentor(s) and the journeymen that drug me around construction sights were very adamant about nomenclature and the neutral was never, never called a ground. That was beat into me, so I naturally try to make that point clear. It would sound as if your friend is old school. Nothing wrong with that and I’m sure he could teach us all a thing or two. It’s just a different world now. Safety is # 1 in the electrical trade nowadays.

Getting back to your problem, I’m clueless to why the lighting circuit would be affecting your HT circuit. I had thought there may be some stray voltage or inductence on the neutral leg from the lighting circuit if they shared the same neutral. You said they don’t, so if this hum is being caused by stray voltage or inductance, it would have to be transmitted from the neutral buss in your panel. I just can’t see this happening. It may just be coincidence that the hum went away when you turned the light off. Can you check this again and confirm that it is a repeatable symptom? If it is, I’ll go to the second floor wehn I get back to the office and talk to an EE/PE I know. He’s nothing short of brilliant and if there is a correlation, he’ll know what it is. This fella is one of the few engineers that came from the trade and then got his degree. RE: an engineer with common sense - a rarity.

Bren,When they say “main panel”; they are referring to the service panel from the power provider (meter base/service panel/line disconnect). And yes, ground rods are still used, and also required for residential applications. Depending on the service / load, the rod can be different sizes and driven to different depths. You also tie the ground rod to the water main coming into the home/facility and the meter base/panel. In industrial applications, this varies. Many plants have a grounding ‘grid’ for lightning protection. You tie the facility into this grid, but again, it’s at the service panel/disconnect to the load side facility.

Have you tried turning off each breaker for the house and rechecking for the static? This would enable you to find the culprit circuit, if its a circuit at all.

Could it be one of your new components has an issue, the Emotiva or monoblocks has a bad internal circuit? Have you tried using just one monoblock then the other to see if only one will cause the static but 2 definately does, obviously. I am thinking the Emotiva has a bad ground or just a bad connection on its boards.

Randy, same here- no harm was meant in nitpicking the terminology- just trying to be clear. I agree, you are getting good advice from your co-worker.

Quote:MDrew said... I had thought there may be some stray voltage or inductence on the neutral leg from the lighting circuit if they shared the same neutral. You said they don’t

I am still unclear if this is true- because of the confusion we may have had in the terminology. I know that you didn't believe it was the lighting circuit because you turned off that breaker and still had the noise, but I would guess that the white wires from both the 20A HT circuit and the 15A light circuit are indeed connected back to the same Neutral bus, and therefore shared. They should be really.

I would agree with you and your co-worker, try the ground isolation first (use a cheater plug so you don't have to physically disconnect the ground). If that solves the issue however, investigate further into the cause as removing the ground should not be a permanent solution.

Good luck Randy, we hope you get it solved and just want to be of help.

Thanks guys for the input. One thing I want to make clear is that I'm trying to remove the "static" sound I'm hearing, not a "hum" sound.

Here are my two situations:

1) Hum - I'm still hearing a just a "little" bit of hum sound from my 80's, but it is hardly noticable unless you get real close to the woofers, etc.. I've heard that a very efficient speaker can produce this sound if your amp has a bit of hum from the transformers. If I place my ear over the top vents of my MPS-1 monoblocks, I can hear a little hum, so I'm guessing it is transferring through the speaker wires to the 80's?

Now, the hum used to be worse when I first hooked everything up. I also heard some "hum" in my vp150 center, which is not going through the amp. Thanks to "Wid", he helped me troubleshoot the issue. My ep600 was sending a hum back through the "Blue Jeans" coax, through my Denon, and to the center speaker. I removed the ground screw on the back of the ep600 and the sound went away totally in the vp150, and greatly reduced the hum in the 80's.

2) Static - I hear some static like sound in the tweeters of my 80's. It sounds almost like when you have a walkie talkie volume turned way down as low as possible. sssssssssshhhhhhhhhhhhhhhhhhhh with a little bit of staticy ticking like sounds mixed in. At first I was lost as this seemed to come and go. As I said before, I figured out that it would go away when I turned on my closet light, which again is on a seperate circuit. Then I turned the breaker on that circuit off, and still hear the noise.

As jakewash mentioned, and my buddy hear at work, I could try one-at-a time turning other breakers off to see when the static goes away. It just is funny that when I turne the closet light on, it goes away. It is almost like by turning on the closet light, it is absorbing the static before it gets to the amp.

Randy,You may have tried this already but are your 60's still kicking around why dont yo0u try them. also could you move the amp somewhere else (away from the closet) and test that way just to help further isolate the prob.Jake

_________________________
------------------------------------------------Leave the gun, Take the canolis.

I talked to Emotiva and I'm going to try a few things to isolate the slight "hum" and "static" issues. One thing is to take a wire and attach it to the Denon chassis and Amp chassis, if the sound goes away it is most likely a ground loop issue, just need to figure it out. The static I'm not sure, I may try a cheater plug to eliminate the round prong to see what happens. He also recommended me checking all the wiring to make sure the ground terminals are in tact.

My understanding now is that the neutral and ground route back to the box and are connected, ultimately to the 6ft ground rod, if I have one of those even.

Quote: As jakewash mentioned, and my buddy hear at work, I could try one-at-a time turning other breakers off to see when the static goes away. It just is funny that when I turne the closet light on, it goes away. It is almost like by turning on the closet light, it is absorbing the static before it gets to the amp.

I would say as was stated earlier the light is acting like a battery/capacitor and is absorbing or grounding the extra energy that your system isn't able to deal with right now. Why? Don't really know, but I'm sure you will find out.

Or you could use an IR or X10 based switch on the closet light and set your remote to turn it on and off at the same time the system gets turned on/off. Might be easier and less frustrating.

Well tonight did a little troubleshooting. The cheater plug did nothing, still static in the tweeters when the closet light switch was off. When the light is on I can still hear a hint of what I'm describing as pink noise in the tweeters and hum in the woofers. But you have to get your ear very very close to hear it. I still hear a very low hummmmm in my amp, which appears to get a little louder when I turn the Denon on or have it in standby mode, weird.

The next thing I tried was taking a long contractor grade extension cord 150ft, and ran it across the basement, upstairs, to the other end of the house, and plugged it into an outlet in the bedroom. Then I ran back downstairs, turned on the amp, still hear the slight humming/buzzing in the amp, and believe it or not, STILL hear static in the tweeters when the AV closet light is OFF.

I also unplugged the amp, and rehooked the left/right speaker wires to my Denon, turned on the Denon and also hear a little pink noise from the speakers, but don't hear the static with the closet light off. I also noticed the Denon gives off a slight hum sound if you get close enough to listen.

I still think when the light is ON for whatever reason, wherever the static is coming from, it is getting absorbed (if that is the word) by the light circuit and not reaching the amp, but when off, the amp is amplifying the static.

I also heard a buzzing in one of my breakers (whirlpool tub/heater) and first thought I was going to have to call the electric company to tighten down the main inlet leads again as your not supposed to hear any buzzing or humming (from arcing). But I think it is just a breaker buzzing.

I am curious if the noise still happens if you cart your Emotiva amp to a friends house. If it does, then I think you can blame the amp (not that you want your amp to be defective, but at least you can determine if it is your house wiring or not, and save you more experimentation time).

I know you don't want to haul M80s to someone else's house. Can you hook up just one QS8 or the VP150 and hear the static? This way you have a smaller speaker to travel with.

the closet light coincidence is really bugging me. in theory, it should have zero effect seeing how it's not tied to the HT circuit. current travels in the direction of least resistance. electrons WANT to find ground. that is why I do not think a separate circuit could affect this as any odd voltage / stray current will seek ground through that neutral buss.

whatever is causing this phenomena, it is common throughout the home, so it would be at the main distribution point. when thinking about this, I believe your main feed MAY have an improperly grounded meter base / service panel. it wouldn't hurt for you take a look at that with a VOM (volt/ohm meter).

just out of curiosity, does this static go away when you turn on any other light? or is it only with this closet light?

Thanks guys for the ideas. I'll see what I can come up with, I do have a multimeter? Is this what your talking about, not sure how to use it or what setting to use, or what to hook it to. It has pin cables and little clamp cables.

I think the 80's being efficient are the cause of some of the faint pink noise I'm hearing. I even hooked them back up to the Denon, and turned the Denon on and nothing else and I can still hear a hint of pink noise and a very very slight amount of hum in the woofers.

Thought I would try to turn one breaker off at a time and see if one eliminates the problem. Also, I'm going to recheck the hookups on the light switch, unscrew the bulbs with the light switch on and see what happens.

I know they are on seperate circuits, but as you have all said, the neutral and ground wires all meet back at the bar in the breaker box. It appears there is a bar on the right side for the rightside breakers, and one on the left side for the left side breakers.

The electrician, for the most part has the neutral (white) and ground (bare) wires seperated and screwed down to seperate screws on the bare. There was a few togethor in the same screw, but most were seperated.

The two lines I ran, 20amp HT breaker and 15amp light/outlet breaker were done similar, however, I did place the ground and neutral under the same screw. I may recheck those and/or seperated them to their own screw. I've heard it is important those screws are tightened down good.

You have grounds and neutrals on the same bus bar???? Tell me, is there a jumper between the right and left bars?

Randy, you better find another electrician with a current fitness card and get that looked at. If I understand correctly what you are describing, it sounds as if you have no ground protection in your home right now. In other words, if you have a short on an appliance and your kid just happens to have one hand on it, and one to a ground source (like a metal sink), he just became the path to ground.

I don't mean to scare you or be mellow dramatic Randy, but I'm beginning to get very concerned about your wiring. Without being there to see for myself what's going on, I'm encouraging you to seek professional, and LICENCED help.

I'm not an electrician by any means but I don't know that I recall ever seeing nor hearing about the neutral (white) and the ground wires being terminated on the same screw. I agree with Mike, I'd certainly be getting a licensed electrician to look at your wiring.

Also, if you are hearing a very faint pink noise I don't know that I'd tear myself ragged trying to locate the source. I had a ground loop problem whenever I placed everything in the new room and still had the slightest of a faint noise from the 80s even after the ground issue was taken care of, such a faint noise that I had to put my ears right up against the speaker to hear it but now I don't even bother trying to locate the source because the noise is that faint ... matter of fact I don't even know if the noise is still there or not, maybe I ought to go see.

Guys, we have a brand new house that is not even 4 years old. The only unlicsened wiring that was done was by me in the basement. The rest of the house, breaker box, outside meter, ground rod, etc was done by a professional licsensed electrician. Stratford would not use some fly by night outfit.

I can tell by the wiring job in the box, the guy knows what he is doing. I can try to take a picture, but I'll try to describe it.

On top of the box, all the home wiring comes into little platic grommets. Then, all the white(neutral) wires seem to be bunched togethor down the back two corners of the box and then are bent into right angles into these bround bars with screws on top. There is a bar vertical on the left and right side of all my breakers, I'm guessing we have at least 15-20 breakers on each side running down the middle of the box.

Now the Black(hot) wires are also pulled togethor and bent at right angles as they go into their prospective breaker.

The bare wires (ground) also run down and then are screwed down into the vertical bars.

On the very top is the main 220 breaker. It has 2 very thick cables with black sheathing, they look to be like 3/4" in diam. There is also one that routes to the side, and is attached to the screw bar where all the white and bare ground wires are screwed down.

First, I shut the main 220volt breaker off. Then I seperated my neutral and bare ground wires and placed them in their own screw down location on the ground bar, to follow the electricians methods. Then I turned everything back on and and no luck, still same problem.

Then I tried turning each breaker off, one by one, hopeing that this would eventually make the static go away, no dice. The only thing I had plugged in was my amp and speakers hooked to that with 12 gauge wire.

Then I turned everything back on, but this time instead of turning the light switch off, I tried unscrewing the 60watt bulbs in the closet. This was interesting, by unscrewing one bulb until it went out, the static increased somewhat. When I unscrewed the second bulb, the static was just as bad as turning the light switch off. My closet is very long, and I have a light fixture at each end. I even tried swapping out the bulbs for 100 watters, no luck.

Right now I'm checking each switch and outlet on the 15amp circuit to make sure my wiring and grounds look ok.

Rick, in regards to the pink noise or hissing noise, it is not real bad at all. Like you said I have to get close to hear it, but I do hear it in all the drivers, tweeter, midrange, woofer. In the woofers it sounds more like a faint 60hz hum.

I'm still trying to figure out if it is normal for the amp to have a very low hummmmm when placing my ears over the vents. The Emotiva tech guy said this amp should be quiet. He described what I said as the term "your amps are singing", which he said this is caused by something in the wiring, I don't know who to believe anymore.

Your desciption sounds like it was done correctly, but you had stated that you had the ground and neutral under the same screw and that should never happen.

Quote: The two lines I ran, 20amp HT breaker and 15amp light/outlet breaker were done similar, however, I did place the ground and neutral under the same screw. I may recheck those and/or seperated them to their own screw. I've heard it is important those screws are tightened down good.

I would say this could be the problem.

The neutral should be on the side of the receptacle with the longer prong opening and the power on the other side and the ground ,bare wire, connected to the box at least, and the ground screw on the receptacle.

>>> I'm still trying to figure out if it is normal for the amp to have a very low hummmmm when placing my ears over the vents. The Emotiva tech guy said this amp should be quiet. He described what I said as the term "your amps are singing", which he said this is caused by something in the wiring, I don't know who to believe anymore.

Randy, I've always thought it was the 80s way of letting me know that it's time to get on with the show.

On the panels I've seen- there are white/Neutral buses down each side (for all white wires only). The bare ground wires have their own bus on one side or the other. These should be separate as Jakewash said. *** So, not only should the white and bare wires not share the same screw, they should not share the same bus either ***.

It should be apparent from looking in the panel that the white and bare ground wires are kept on separate bus connecting bars. Does this look like what you see? If you have a white or ground out of place you should be able to correct that.

What did you think of trying the amp at a friends or neighbors? I know it's a pain- but I would hate to see you rewire your entire house and find out it was the amp. I would first separate the grounds and neutrals however, as they may be the problem, and should be separate anyways.

Quote:On the panels I've seen- there are white/Neutral buses down each side (for all white wires only). The bare ground wires have their own bus on one side or the other. These should be separate as Jakewash said. *** So, not only should the white and bare wires not share the same screw, they should not share the same bus either ***.

Correct... there is a neutral bus bar and a ground bar, ne'er the t'wain shall meet (except through the neutral bond).

If you do have neutral and ground wires on the same bus bar, you do have a problem. No matter how nice your builder's office is and how expensive the salesman's suit was, something went wrong.

Well Randy, as I said when I suggested that you put the closet light on while listening, I continued to read this and ponder, but nothing sensible resulted(the closest was that the Emotiva brought evil spirits into the closet which were subdued by the friendly spirits activated by the lights).

I'll comment on some of your other points. It isn't unusual for there to be a very low mechanical hum from the transformer when you put your ear just above the top vents. The three receivers that I use do this, but it isn't audible a couple feet away. The alternating magnetic fields in the transformer can vibrate the laminations in tune with the 60Hz power. A toroidal transformer, such as those the Emotiva uses, is supposed to be less susceptible to hum because the core is more tightly wound. My stuff can't be heard beyond a few inches, so it's effectively noise-free, and I'd think that the same would apply to the Emotiva.

As to the electrical(as opposed to mechanical)hum or hiss at a very low level heard with your ear next to the speaker, again with my receivers turned up to maximum gain(with nothing playing, of course)a faint hiss from the tweeters and faint hum from the woofers is heard a few inches away, but there's nothing at the level settings that are commonly used. So, in effect the equipment is both mechanically and electrically noise-free and isn't a cause for concern.

Here are the pics of the breaker box. There is a bar on both sides, connected by some type of strap at the bottom, all hooked to the heavy black cable on the top right next to the main power breaker that feeds the entire system. The second picture shows how the are all screwed down to the ride side. The left side is similar. I find it hard to believe it is wired wrong, we've lived hear for 4 years and have had no issues. Also, all electricians in Iowa, Illinois, etc. belong to the Union and are certified and must follow strict building code guidelines. You guys really think this is incorrect?

ps: nevermind the cheap power bar to the right, that just powers my DSL wireless modem and network router which is hooked to a 110 block.

Thanks John, I feel better knowing the low electrical hum from the woofers and hiss from the tweeters (faint with ears very close) may be normal. I also hear it with the Denon, so it must not be the amp.

The static issue is really getting stranger, the more troubleshooting I do. Today I turned every breaker off, one by one in the entire house. When I was done, the only breaker on was the 20amp feeding my HT area. There was still static in the tweeters, just like when I have the other 15amp light circuit on with the closet light on.

I thought I was onto something, but soon got more confused. I checked the lights on the ceiling of the closet which are connected to the closet switch. The lights are just the cheap ceramic kind you get at most improvement stores for closets.

Anyway, I turned the power off to the 15amp circuit so I could look at the wiring. For light so I could see what I was doing, I used my halogen work light and ran a long extension cord to another part of the basement for power. The first light checked out ok, so I proceeded to look at the second light at the end of this switch circuit. I noticed I only had the black and white wires hooked up. These ceramic lights have two gold screws for power, and two silver screws for neutral, but really don't have a green screw for the ground, like switches and outlets.

So I thought since the neutral and grounds come togethor back at the circuit box, I would try hooking the ground to the other silver screw. Once done, I jumped down and ran over to the speaker. YESSSSS the static was gone.

But, my excitement quickly ended when I turned off the halogen light, the static came back. WHAT, how can this be, it doesn't make sense.

What is really funny is, I can set the halogen light just inside the door turned on, and the static goes away. If I move it outside the closet door a few feet the static comes back.

It is almost like there is some darn force field at my doorway to the closet. If there is a light source, closet or other source, the static goes away when the light is powered. I'm going nuts.

The closet dimensions are probably 4ft x 12ft, very long and narrow. When you first walk in the door there is a switch which powers two 60watt bulbs, one at each end of the closet. The AV stuff is at the other end.

Sounds very frustrating Randy- I'm sorry. I know you'll get to the bottom of it. Look on the "bright" side (pun intended) - if we don't figure it out you can start selling the latest greatest snake oil product: "The audio purifying bulb" and make yourself rich

Thanks for posting pictures of your panel (and the amp in the other thread- very nice ) Not that I've seen tons of panel installations, but I'm confused by what I am seeing. Those two bars full of screws down each side look like the neutral bus, connected together with the strap at the bottom as one would expect. I wish I could enlarge the pic more, but it sure looks like the grounds are connected to the same bus?!? I've never seen this before myself. Although I can't make out a separate grounding strap where the grounds should go.

Strange to me, but I'm no expert. Hopefully some of the others with more knowledge on this can make better sense of it.

One thing I know for sure, we need to resolve this quick so you can get back to more important things, namely enjoying the system instead of this headache. Oh, and I think I speak for all of us when I say... "bring on the pics of the new speakers!"

Well here is a paragraph out of the book I purchased from Menards when I wired my basement. According to this the neutral AND bare and/or green wires connect to the neutral bar, which ultimately hook to the ground going to the ground rod in the yard.

"The main neutral wire is connected to the neutral bus bar. This bar is connected to a system ground wire, which leads to a grounding rod. White wires for every circuit, and possibly bare or green ground wires, also connect to the neutral bus bar. As a result, each 120-volt circuit has a black or colored wire leading from a circuit breaker, a white wire leading to the neutral bus bar, and possibly a bare copper or green-covered ground wire also connected to the neutral bar. "

Very interesting Randy. It sounds correct according to the book for sure. I haven't seen it in my area, but as I said before I'm no expert so there for sure is much I don't know.

I knew that eventually both are connected back to ground, but in my case it isn't done at the panel. I believe it is back at the main service/shutoff panel which is on the outside of the house with the utility co. power meter.

Silly about the location of the publisher on the book. I guess the local electricians here get there books elsewhere.

John, wow! Good find. It does look like the same type of idea. There you go Randy, for only $100 you can convert line noise into light.

You've got great advice from everyone in this thread about troubleshooting circuits but as I thought it might be worthwhile taking another look at the amp itself. I've never heard it so I checked the specs which generally look pretty good but this commentary about the signal to noise ratio caught my eye. As we all know the M80s are very transparent because they are so linear so those tweeters will be more sensitive to any HF noise. The following discussion was from the Audioholics article. Gene DellaSalla's measurements showed an unflattering noise profile for this amp.

"Signal to Noise Ratio (SNR) Measurements

Measuring the Signal to Noise ratio of this amplifier proved to be quite challenging due to the lack of proper LPF for limiting the bandwidth to below the switching frequency.

By applying A-weighting response curve, I was able to achieve partially reasonable measurements of 82dBA (A-wt) at 1 watt or about 102dBA at 270wpc.

From Emotiva Engineering Labs:We perform my signal to noise ratio test a little different than you do. We base our measurement strictly on the rms voltage as measured on the AP with a <10Hz to 30Hz bandwidth selected. No other weighting is applied. The amplifier is connecting to a purely resistive load, in this case 4 ohms. We measured a noise floor voltage of 268uV using the balanced output of the AP with a 50 ohm output impedance - generator selected to off to terminate the input to the amplifier. From this starting point we let the AP do all the work. We select the output level from which I want the S/N ratio to be referenced at and call that the 0dB point. Below are some measurements we have taken:

102dB ref 300W 101dB ref 270W 87 dB ref 10W 77dB ref 1W

These numbers should be more consistent with what you are hearing from the amplifier. Also, we believe these numbers represent a best case scenario because we are using the balanced input. The key to this test is the noise floor of the amplifier. This can change significantly if power cables are inducing 60Hz into signal, other equipment could be radiating noise, etc.

In any event, the 77dB @ 1 watt number isn’t flattering to say the least, but given the unique amplifier topology, I suspect the out of band switching noise is producing a non representative number since noise was never an audible issue in real world listening tests. When using the Yamaha RX-V2500 as the preamp for the Emotiva MPS-1, the set-up was dead quiet and sounded as silent as other amps I have measured with significantly lower noise floors. "

I also noticed that he ranked the signal to noise ratio lowest among his performance parameters. I know you tested the Denon as well but it may be worth focussing on the amp itself as a noise source. Sometimes its a compatiblity issue with the pre-amp. If you were nearby I'd lend you one of my Brystons for comparison.

Each amp does have it's own fan, however, they never run unless pushed to extreme situations.

Just to let everyone know, the problem is resolved. After moving the amp to the kitchen and having the same issue, using the kitchen lights, then going over to a friends house and having the same results, I called Emotiva and worked it all out.

The folks answering the phones at Emotiva are actually the engineers and designers of their own products, not some kid reading off a computer screen.

Anyway, after explaining the situation, the person I talked to had a good idea what was going on. He sent me two new amps, but first tested them in the lab and even made a modification to something on the circuit board.

Quote:Anyway, after explaining the situation, the person I talked to had a good idea what was going on. He sent me two new amps, but first tested them in the lab and even made a modification to something on the circuit board.

I want to know what they did!

Glad its fixed.

Sherwood or Emotiva....Sherwood or Emotiva... Sherwood or Emotiva... I am so confused

I will find out again on Monday when Emotiva is back in the office. The engineer I talked to, explained it to me the other day before sending me the amps, but much of his information was over my head. I compared the circuit boards side by side and I noticed on the new ones, one of the components had some type of little rectangular cap over the top of the piece soldered to the board.

He said at one time they had some amps coming from their factory and one of the screws on the board(ground) was over torqued, which caused two of the items on the board to make contact, which in turn created almost like a "antenna" or "receptive" type scenario. He thought it was possible I received some that they missed checking inventory.

Anyway, I will find out and let you all know.

One thing he mentioned, and had to be real careful as their company "Jade Designs" is under confidential agreements with all the manufacturers they design for, is they actual are the Research, Design, and Engineers for many of the BIG players in China and other locations who make receivers and amps.

He mentioned in reality, there is really only like 7 or less BIG Players out there that make the electronics which go into todays amps/avr's. They are actualy a Engineering and Design company which have worked with many of the high-end ($$$$$) companies out there.

They decided to start their own product line using many of the same components, since they designed them, which are used in many NAME brand companies out there. They wanted a direct channel to the customer (like Axiom) to save costs versus going through dealers. However, they are required to not disclose the names of those companies per their relationship.

For the past 3-4 years they used AV123 as a distribution channel and had a great relationship with Mark, the owner of AV123's products. They have now decided to sell their own products directly on http://www.emotiva.com .

In addition, their prices have dropped about 30% since their introduction 4 years ago on AV123, but their quality has not.

ps: Someone on AV123 had told me once they design products for Krell and Sunfire Carver, just to name a few. He did not confirm this or deny this to me, but hinted of the truth to this statement, but could not go into the details per legal reasons.

Quote: Sherwood or Emotiva....Sherwood or Emotiva... Sherwood or Emotiva... I am so confused

I know the confusion. I'm stuck between Denon 4306, S/N R-972 (available who knows when), and Emotiva MMC-1/IPS-1 combo (available in 3 weeks). I was also looking at an Outlaw pre/pro separate, but after some looking the complaints were beyond the quality of the remote or how well Audyssey defined speaker distances. I really like the ethernet plug-in of the Denon, but have since found what appears to be an ethernet to RCA output converter that makes up for the difference in price, and then some.

My concern with the emotive is the HDMI connections. Does it upconvert or not? The way I read it is that it's a pass thru setup.

Ok, here I go on trying to explain this issue. I talked to the engineer so bare with me if I don't explain it properly.

My understanding was that these amps have voltage regulators that operated in a very high bandwidth (mhz). Over the years, they have had a few calls from people experiencing a similar "static" in their speakers from the amp.

One example that can cause this problem is microwave repeater towers in your area interfering with these higher frequency ranges on the regulators.

What he did to resolve the problem was to place a "cap" on the voltage regulator that basically changes or lowers the frequency bandwidth somewhat, so that it no longer receives the interference. He could not explain why by turning on the lights in the vicinity eliminated the static.

Anyway, the static is totally gone now and I can enjoy movies with the lights off.

In the future I have to make sure I mention this issue if I add additional modules to my chassis.

The reason they do not "cap" all of the amps sent out, is because in theory by lowering the frequency bandwidth, it would make it more susceptible for interferences. For whatever reason, I must live near something that the higher bandwidth won't work.

Lonnie knows his $hit, that is for sure. Also being a former Certified Electrician, he said what some people mentioned above is incorrect about the neutral/ground bars. It is national code that the neutral and grounds go to the same bar and ultimately route to the ground outside. It is up to the electrician's style as to if they like to have a "clean look" and put the grounds on one side and the neutrals on the other. The strap at the bottom brings them togethor, so there is no difference, it is just a matter of installation preference.

Anyway, I'm not going to worry about it anymore, just ENJOY the tunes.

Link - page two, starting bottom left column and moving into the middle column on why it most certainly DOES break the NEC.

The two are connected (here at least) at the main breaker panel to protect 2-prong appliances, offering a path to ground if there is no 3rd prong on an appliance... the problem with bonding them at the bus bars is that:

A) You create new ground planes for every circuit in the house... without a common grounding point, you end up with different potential between different wire runs. Now, this naturally occurs anyway, since there is no effort ever to make sure every run in the house has the same resistance from end to end... but this aggrevates the problem.

B) From a safety standpoint, when a ground is activated (say a hot wire slips out of a screw on an outlet and hits the metal box)... in a correctly wired system, that voltage will be carried back to ground at the box, incorrectly bonded neutrals could provide a "least resistance" path back the other way, putting voltage back into the house on the neutral wire - now white & ground have a potential difference of 115VAC as well as black & ground... what's so bad about that? The black (hot) leads are protected by circuit breakers. Neutrals are never, EVER protected. Sure the faulted breaker will eventually trip, but maybe not before you get hurt. Also, looking at feeding back voltage through a neutral wire, you end up with yet another fun AC fact... the potential difference between two different hots is 240VAC, which can be lethal.

You should watch a show on HGTV some night called Holmes on Homes. It is a Canadian Production, but to get to my point, he is pissed at minimal code requirements and contractors who use them to save money. hence the cable runs. But, just because your house is newer doesn't mean some contractor didn't try to save a few $$ and time is money.

But, on issue I also had a hum from a HK sounded lie a bunch of bee's they told me it was my house wiring. I sent it back not once but 4 times and still had hum. Finally they replaced it with a newer one and hum dissapeared. and I practically re-wired my living room and half the house. try another amp at your house or take yours and the speakers to another place.And the ground is a safty issue big time if a hot gets lose at least it will trip the circuit breaker. If the box and even the recepticle is NOT grounded and a hot wire gets lose who ever touches the appliance box just because amplified

I am not a electrician but, did take a first year apprentice course years ago.And I was taught there and it was stressed NEVER put Nuetral wires and Graounding wires on the same buses. Actually I can be corrected but, I thought there was a Neutral bus bar and a seperate Grounding bar.Neutral wiring still carries current after it passes through a appliance which takes it to the Neutral bar. Which I was always under the assumption that it was an isolated bar that is linked to the Neutral wire coming into the home and takes the load back to the Power company. The ground bus bar is wher all grounds tie into go to the grounding rod or water pipe if you are in a town.